Biometrics identifies an individual by utilizing special characteristics in the biological information of the individual and has attracted attention in recent years. The biological information may be fingerprints, the iris (of the eye) or blood vessel patterns (veins), etc.
Biometrics offers the advantages of being highly convenient and secure. Biometrics is convenient and secure because no key needs to be carried and there is little threat to security from loss or illegal actions such as theft.
In biometrics, authentication by use of blood vessel patterns (vein identification) is becoming widespread. Blood vessel patterns are internal bodily information so falsification is difficult compared to fingerprints and vein authentication therefore offers higher security than fingerprints. Moreover, blood vessel (hand vein) authentication does not require irradiating light onto the pupil of the eyes such as in retinal scans. There is therefore little psychological resistance to blood vessel authentication among users and it is highly safe.
A blood vessel (or vein) authentication device is disclosed for example in JP-A-07-021373 (1995). The blood vessel authentication device irradiates near-infrared light onto the subject. The blood vessel authentication device then projects transmitted light and reflected light by utilizing an image sensor. In this case, the hemoglobin in the blood fluid absorbs most of the near-infrared rays. The blood vessel authentication device can therefore draw the vein pattern on the projected image. The blood vessel authentication device judges whether or not the vein pattern drawn in the projected image matches the pre-registered vein pattern. The blood vessel authentication device then identifies the individual based on the judgment results.